The present invention relates to a procedure for bringing a rotating body, which is made to rotate by means of a drive, to a standstill at the completion of a work cycle, particularly a rotating body which is placed in bearings in a balancing machine for evaluation with respect to its unbalance.
A procedure is known from DE-AS No. 10 82 066 for balancing rapidly turning machine rotors, particularly of steam turbines and turbo-generators, wherein prior to the balancing process the rotors are brought to a high speed by means of a drive and subsequently disconnected from the drive prior to the actual balancing. The procedure is characterized in that after the balancing process the drive for the balancing body is brought to exactly the same rotating speed as the balancing body. Moreover, when the balancing body and the drive of the balancing device are exactly the same speed, coupling bolts of a coupling device connected to the drive reengage with a coupling disk located on the freely rotating rotor whereupon the rotor is brought to a standstill in short order by means of the drive motor which then functions as a generator. A procedure of this nature is not suitable for bringing a rotating body under investigation to a standstill when a specific point at its circumference is in a certain relation to a point on the balancing machine. For this purpose, an additional indexing procedure is required to locate the rotating body after it is brought to a standstill at an angular position which has been determined during the measurement as an unbalance angle position. The unbalance can subsequently be eliminated at this point by means of machining, for example. Such additional indexing procedures are time-consuming and also cause considerable delays, especially when a balancing machine is installed in a production line. This is particularly true when the point on the rotating body which is to be machined must be indexed to a position in front of a machine tool attached to the balancing machine, which machine tool is not positioned at the assumed zero point for the identification of the unbalance. In such a case, and after the body is brought to a standstill, it is generally necessary to first index the rotating body into that position which corresponds to the coordinate system selected for the unbalance, and subsequently to bring the point to be processed up to the correction tool in a second indexing procedure. It is obvious that the cycle time of the production line is considerably influenced by such an indexing procedure.
Another procedure for balancing rotors is known from DE-AS No. 12 48 335 wherein the drive motor is disconnected from the balancing body after it has reached its speed and then run up to speed a second time after the measurement for reconnection to the balancing body when the motor and the balancing body have the same speed. This is done in order to brake the balancing body by means of the motor. The procedure is characterized in that the energy supply to the drive motor is disconnected as soon as the motor has reached the speed of the balancing body during the second run-up. This procedure for bringing a rotating body to a standstill is not suitable for decreasing the required time for bringing a rotating body to a standstill at a predetermined point for the same reasons discussed above in connection with DE-AS No. 10 82 066.
In the area of machine construction it is frequently necessary to brake rotating bodies of various moments of inertia from their rotating movement in such a manner that they are brought to a standstill at a specific final position. Thus, with respect to turning machines, for example, it is desirable to stop the chuck for the rotating body to be placed in it at a specific point for purposes of opening it. In addition, after the measuring run it is important that the body under investigation in a balancing machine be stopped directly in front of the correcting machine tool. Such is important since the correction point identified during the unbalance measurement may be located at any point on the circumference of the rotor depending upon the location of the unbalance.
As needed, an electric motor, a turbine, or compressed air acting directly at the rotatable body may be used as the drive for the abovementioned general machines and balancing machines. Also direct coupling with the rotating body may be used if the drive comprises an electric motor or turbine. Connection with the body under investigation may be provided via a gear or drive belt. The drive may also be connected to a shaft, on the end of which the chuck of a turning machine or the seat for a vehicle wheel is arranged. The other end of the shaft accommodates an angular reference plate with a fixed connection to the shaft.